A131712 Period 4: repeat [1, 3, 7, 9].

1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1, 3, 7, 9, 1

Offset

0,2

Comments

Decimal expansion of 1379/9999. - Klaus Brockhaus, May 21 2010

Links

Table of n, a(n) for n=0..104.

Index entries for linear recurrences with constant coefficients, signature (0,0,0,1).

Formula

G.f.: (1+3*x+7*x^2+9*x^3)/((1-x)*(x+1)*(1+x^2)). - R. J. Mathar, Nov 14 2007

From Wesley Ivan Hurt, Jul 09 2016: (Start)

a(n) = a(n-4) for n>3.

a(n) = 5 - 3*cos(n*Pi/2) - cos(n*Pi) - 3*sin(n*Pi/2) - I*sin(n*Pi). (End)

Maple

seq(op([1, 3, 7, 9]), n=0..40); # Wesley Ivan Hurt, Jul 09 2016

Mathematica

PadRight[{}, 100, {1, 3, 7, 9}] (* Wesley Ivan Hurt, Jul 09 2016 *)

Prog

(PARI) a(n)=1+2*(n%4)+2*(n%4\2) \\ Jaume Oliver Lafont, Aug 28 2009
(Magma) &cat[[1, 3, 7, 9]: k in [1..30]]; // Vincenzo Librandi, Nov 23 2010

Crossrefs

Cf. A072845, A131707.

Cf. A178148 (decimal expansion of (243+17*sqrt(285))/402). - Klaus Brockhaus, May 21 2010

Sequence in context: A244338 A336045 A090458 * A072845 A197481 A197682

Adjacent sequences: A131709 A131710 A131711 * A131713 A131714 A131715

Keyword

nonn,easy

Author

Paul Curtz, Sep 14 2007

Extensions

More terms from Klaus Brockhaus, May 21 2010

Status

approved